The present invention relates to a technical field of a cable drag chain, which holds and guides an electric cable or a hydraulic or pneumatic hose between a mobile portion where a machine tool, a civil engineering machinery, a transfer system or the like is moved and a fixed portion.
When a cable or a hydraulic or pneumatic hose is connected to a mobile device such as a machine tool, a civil engineering machinery, a transfer system or the like, undue torsion or tension is generated in the cable or hose by its movement thereby damaging a cable or a hose and disordering its outward appearance. Therefore, a cable drag chain for holding and guiding the cable or hose has been proposed.
A support device for a cable or a hose, which was proposed in Japanese Examined Patent Publication No. Sho. 62-15008 for example, includes a plastic small-diameter tube member provided with a fan-shaped groove in upward and downward directions of an outer peripheral surface of its side, inside the support device, and also includes a half body of the tube member made of a metallic sheet up and down respectively on the inside the support device, and the halves of the tube members are attached to each other with a pin in such a manner that said small diameter tube member is sandwiched by the halves of the tube members from the upper and lower portions. Then by engaging the inner groove in the small diameter tube member and a stopper of the upper and lower halves of the tube members the support device has a structure connected in the longitudinal direction of the support device.
A cable drag chain xe2x80x9cAxe2x80x9d disclosed in the specification of Japanese Patent Application No. 2000-278471 previously filed by the present inventor includes a pair of connector pins A34 and pin hole portions A35 at a front end portion A32 and a rear end portion A33 in a plurality of tubular intermediate frames A3 respectively as shown in FIGS. 4 and 5. Then, the end surface of each of the front and rear end portions A32 and A33 is formed as a stopper surface, which limits a bending angle, and the connector pin portion A34 and the pin hole portion A35 of the adjacent intermediate frame A3 are engaged to each other thereby connecting a plurality of intermediate frames A3. At the same time an outer periphery of the connected portion of the adjacent intermediate frame A3 is covered with a detachable tubular outer frame A4 to close a gap between the adjacent intermediate frames A3.
Problems to be Solved by the Invention
However, when the pin for engagement in the former support device for the cable or hose is removed, the upper and lower tube member halves and the small diameter tube member are taken apart in pieces and they are disconnected at the disassembled portion. Thus, assembling them to the original structure is troublesome. Further, there are problems that after the upper and lower tube member halves and the small diameter member are assembled once, it takes much time to disassemble them and when they are assembled again, a pin must be replaced with a new one, thereby increasing the cost and becoming inconvenient for maintenance.
Further, there are problems that since the upper and lower tubular member halves are made of a metallic material and the small tube member are molded of a synthetic resin, the metallic material shaves the synthetic resin during sliding and a large amount of wear powder is produced. Further, since the metallic material is used the holding device becomes heavier than that molded of only a synthetic resin. Additionally since a portion of a metallic material and a portion of a synthetic resin collide with each other during moving the support device, a high noise is generated. Furthermore, since the upper and lower tube member halves on the outermost periphery is made of metal the noise that the upper frame hits a floor surface during the movement of the device becomes higher.
On the other hand, in the latter cable drag chain A an intermediate frame A3 is formed by a thick hollow rectangular tube body of a synthetic resin and there is a troublesome problem that the cable or the hose cannot be inserted during maintenance and repair as shown in FIG. 5(a). Further, as shown in FIG. 5(b) a thin tongue piece A47 provided on the outer frame A4 is engaged in a groove portion A36 provided on the outer peripheral surface of the intermediate frame A3 to close the gap of the connecting portion. However, the thin tongue piece A47 makes the contact conditions with the intermediate frame A3 insufficient and the sealing degree cannot be exerted sufficiently.
Therefore, the objects of the present invention is to solve the above-mentioned problems and to provide a closed cable drag chain, which is capable of preventing the contact wear powder generated in the holding and guiding the cable or the like from being scattered by reliably closing the cable or the like, and wherein the assembling, maintenance and repair are easy while having light weight and low noise.
Means for Solving the Problems
To solve the above-mentioned problems a closed cable drag chain according to claim 1, into which a cable or the like is inserted to be held and guided in conditions where a number of intermediate frames are articulately connected to each other, an outer frame including a removable opening/closing frame structure fit-covers a coupled portion of the adjacent intermediate frames to close the coupling gaps respectively thereby engaging it in a tubular shape is characterized in that said intermediate frame comprises an intermediate frame body in which a cable holding groove was provided and an opening/closing lid member fitted into said cable holding groove, and said intermediate frame body includes lower open end surfaces, which abut with each other on the chain bend inner peripheral side to hold a required bending position of the chain and upper open end surfaces, which abut with each other on the chain bend outer peripheral side to hold a straightly extended position of the chain.
A closed cable drag chain according to claim 2 further solves the above-mentioned problems by that fact that an elastic sealed portion, which closely fits said outer frame and said intermediate frame are formed on the inside of the front end and the inside of the rear end of the outer frame in addition to the configuration of claim 1.
Further, a closed cable drag chain according to claims 3 and 4 further solves the above-mentioned problems by the fact that said outer frame is relatively movably connected to said opening/closing lid member while including an engagement piece, which is movably engaged in an engagement portion protruded on the opening/closing lid member in the coupling direction of the chain in addition to the configuration according to claim 1 or 2.
Further, a closed cable drag chain according to claims 5, 6, 7 and 8 further solves the above-mentioned problems by the fact that said intermediate frame and outer frame are formed of a synthetic resin in addition to the configuration according to claims 1 to 4.
Here, the intermediate frame used in the present invention comprises an intermediate frame body in which a cable holding groove is provided and an opening/closing lid member, which is fitted into said cable holding groove. If the intermediate frames forms a tubular coupling structure in which they were articulately connected to each other and has a form in which a cable or the like is inserted and can be held and guided, any annular forms having cross-sections such as a circular cross-section, an oval cross-section, a rectangular cross-section and the like may be used.
Further a number of intermediate frames in the present invention may be used if they are articulately connected to each other in a coupling structure. As the concrete connection structures a connecting structure in which connecting pin portions of the adjacent frames and the pin hole portions of the adjacent intermediate frames were fitted to each other, a connecting structure in which the pin hole portions of the adjacent intermediate frames were connected to a connecting pin of another part or the like can be adopted.
On the other hand, if the opening/closing frame structure of said outer frame can be removed from the coupling portion of the adjacent intermediate frames, any of the opening/closing frame structures, which can be split or opened/closed up and down or left and right, may be used. Further, if an opening/closing mechanism including a snap locking portion on one hand and including a hinge portion on the other hand is adopted, a simple opening/closing operation can be attained.
Further, if the elastic sealed portion formed inside the front end and inside the rear end of said outer frame can closely fits the outer frame and the intermediate frame, even a sealing form integrally molded by a multi-components injection molding process may be used and a sealing form in which an elastic sealing member was adhered with adhesive or the like may also be used.
If the engagement structure of the engagement piece formed on said outer frame and the engagement portion protruded on the opening/closing lid member is a structure that can relatively movably connect the outer frame to the opening/closing lid member, any engagement structure may be used. Even if, for example, said engagement structure is one in which the engagement portion is formed of a stopping projection and an engagement hole, which is movably engaged with this stopping projection in the coupling direction, is provided in an engagement piece, it may be used.
If the materials of the intermediate frame and the outer frame are synthetic resin, any material may be used. Nevertheless, synthetic resins such as acryl so called as engineering plastics having excellent wear resistance and lubricating properties, polycarbonate, nylon 6, nylon 66, nylon 46, all aromatic nylons and the like are preferably used. Further, when strength is required, fiber reinforced plastics is preferred.
Action
When a mobile machine such as a machine tool, an electronic device, a civil engineering machinery, a transfer system or the like, or a cable or the like such as an electric cable, which performs electrical supply, liquid supply or the like to a mobile portion of a machine, a hydraulic or pneumatic hose or the like is moved together with the mobile portion, the closed cable drag chain according to the present invention sequentially causes portions exhibiting required bending positions of a number of adjacent intermediate frames coupled in a tubular shape to sequentially displace in accordance with the mobile positions of mobile portions while lower open end surfaces formed on the intermediate frame bodies of the intermediate frames abut on each other on a chain bend inner peripheral side thereby ensuring a required bending radius, whereby the cable or the like can be moved together with the mobile portion of the machine while being held and guided.
Further, upper open end surfaces formed on the intermediate frame bodies of the intermediate frames abut on each other on a chain bend outer peripheral side at mobile positions where said adjacent intermediate frames do not require a required bending position, whereby the drag chain allows the cable or the like to be inserted and held while maintaining a straightly extended position.
A better understanding of the invention will be had when reference is made to the Brief Description of the Drawings, Description of the Invention and claims which follow hereinbelow.